'use strict'
const path = require('path')
const defaultSettings = require('./src/settings.js')

function resolve(dir) {
    return path.join(__dirname, dir)
}

const name = defaultSettings.title || 'vue Admin Template' // page title

// If your port is set to 80,
// use administrator privileges to execute the command line.
// For example, Mac: sudo npm run
// You can change the port by the following methods:
// port = 9528 npm run dev OR npm run dev --port = 9528
const port = process.env.port || process.env.npm_config_port || 9528 // dev port

let cdn = { css: [], js: [] }
    // 通过环境变量 来区分是否使用cdn
const isProd = process.env.NODE_ENV === 'production' // 判断是否是生产环境
let externals = {}
if (isProd) {
    // 如果是生产环境 就排除打包 否则不排除
    externals = {
        // key(包名) / value(这个值 是 需要在CDN中获取js, 相当于 获取的js中 的该包的全局的对象的名字)
        'vue': 'Vue', // 后面的名字不能随便起 应该是 js中的全局对象名
        'element-ui': 'ELEMENT', // 都是js中全局定义的
        'xlsx': 'XLSX' // 都是js中全局定义的
    }

    cdn = {
        css: [
            'https://unpkg.com/element-ui/lib/theme-chalk/index.css' // 提前引入elementUI样式
        ], // 放置css文件目录
        js: [
                'https://unpkg.com/vue/dist/vue.js', // vuejs
                'https://unpkg.com/element-ui/lib/index.js', // element
                'https://cdn.jsdelivr.net/npm/xlsx@0.16.6/dist/xlsx.full.min.js', // xlsx 相关
                'https://cdn.jsdelivr.net/npm/xlsx@0.16.6/dist/jszip.min.js' // xlsx 相关
            ] // 放置js文件目录
    }
}

// All configuration item explanations can be find in https://cli.vuejs.org/config/
module.exports = {
    /**
     * You will need to set publicPath if you plan to deploy your site under a sub path,
     * for example GitHub Pages. If you plan to deploy your site to https://foo.github.io/bar/,
     * then publicPath should be set to "/bar/".
     * In most cases please use '/' !!!
     * Detail: https://cli.vuejs.org/config/#publicpath
     */
    publicPath: '/',
    outputDir: 'dist',
    assetsDir: 'static',
    lintOnSave: false,
    runtimeCompiler: true, // 使用包含运行时编译器的Vue内核版本
    productionSourceMap: false,
    devServer: {
        port: port,
        open: true,
        overlay: {
            warnings: false,
            errors: true
        },
        // 代理跨域的配置
        proxy: {
            //本地请求有/api的时候，会代理请求地址向另外一个服务器发起请求
            '/api': {
                target: 'http://ihrm-java.itheima.net/', //跨域请求的地址
                changeOrigin: true //当值为true的情况下，才表示开启跨域
            }
        }
    },
    configureWebpack: {
        // provide the app's title in webpack's name field, so that
        // it can be accessed in index.html to inject the correct title.
        name: name,
        resolve: {
            alias: {
                '@': resolve('src')
            }
        },
        // 要排除的包名 key:value key要排除的包名  value实际上是实际上引入的包的全局的变量名   
        //因为要排除element-ui所以后面要引入CDN文件 中又ELEMENTUI的全局变量名
        //externals首先回排除，定义的包名 空出来的位置 会用变量来替换
        externals: externals
    },
    chainWebpack(config) {
        // it can improve the speed of the first screen, it is recommended to turn on preload
        config.plugin('preload').tap(() => [{
            rel: 'preload',
            // to ignore runtime.js
            // https://github.com/vuejs/vue-cli/blob/dev/packages/@vue/cli-service/lib/config/app.js#L171
            fileBlacklist: [/\.map$/, /hot-update\.js$/, /runtime\..*\.js$/],
            include: 'initial'
        }])

        // 注入cdn变量
        //这行代码 会在执行打包的时候 执行 就会讲cdn变量注入到html模板中
        config.plugin('html').tap((args) => {
            // args是注入html模板的一个变量
            args[0].cdn = cdn //后面的cdn就是定义的变量
            return args //需要返回这个参数
        })

        // when there are many pages, it will cause too many meaningless requests
        config.plugins.delete('prefetch')

        // set svg-sprite-loader
        config.module
            .rule('svg')
            .exclude.add(resolve('src/icons'))
            .end()
        config.module
            .rule('icons')
            .test(/\.svg$/)
            .include.add(resolve('src/icons'))
            .end()
            .use('svg-sprite-loader')
            .loader('svg-sprite-loader')
            .options({
                symbolId: 'icon-[name]'
            })
            .end()

        config
            .when(process.env.NODE_ENV !== 'development',
                config => {
                    config
                        .plugin('ScriptExtHtmlWebpackPlugin')
                        .after('html')
                        .use('script-ext-html-webpack-plugin', [{
                            // `runtime` must same as runtimeChunk name. default is `runtime`
                            inline: /runtime\..*\.js$/
                        }])
                        .end()
                    config
                        .optimization.splitChunks({
                            chunks: 'all',
                            cacheGroups: {
                                libs: {
                                    name: 'chunk-libs',
                                    test: /[\\/]node_modules[\\/]/,
                                    priority: 10,
                                    chunks: 'initial' // only package third parties that are initially dependent
                                },
                                elementUI: {
                                    name: 'chunk-elementUI', // split elementUI into a single package
                                    priority: 20, // the weight needs to be larger than libs and app or it will be packaged into libs or app
                                    test: /[\\/]node_modules[\\/]_?element-ui(.*)/ // in order to adapt to cnpm
                                },
                                commons: {
                                    name: 'chunk-commons',
                                    test: resolve('src/components'), // can customize your rules
                                    minChunks: 3, //  minimum common number
                                    priority: 5,
                                    reuseExistingChunk: true
                                }
                            }
                        })
                        // https:// webpack.js.org/configuration/optimization/#optimizationruntimechunk
                    config.optimization.runtimeChunk('single')
                }
            )
    }
}